2 * i2c.c - driver for ADI TWI/I2C
4 * Copyright (c) 2006-2014 Analog Devices Inc.
6 * Licensed under the GPL-2 or later.
8 * NOTE: This driver should be converted to driver model before June 2017.
9 * Please see doc/driver-model/i2c-howto.txt for instructions.
16 #include <asm/clock.h>
20 static struct twi_regs *i2c_get_base(struct i2c_adapter *adap);
22 /* Every register is 32bit aligned, but only 16bits in size */
23 #define ureg(name) u16 name; u16 __pad_##name;
46 #define TWI0_CLKDIV TWI_CLKDIV
47 # ifdef CONFIG_SYS_MAX_I2C_BUS
48 # undef CONFIG_SYS_MAX_I2C_BUS
50 #define CONFIG_SYS_MAX_I2C_BUS 1
54 * The way speed is changed into duty often results in integer truncation
55 * with 50% duty, so we'll force rounding up to the next duty by adding 1
56 * to the max. In practice this will get us a speed of something like
57 * 385 KHz. The other limit is easy to handle as it is only 8 bits.
59 #define I2C_SPEED_MAX 400000
60 #define I2C_SPEED_TO_DUTY(speed) (5000000 / (speed))
61 #define I2C_DUTY_MAX (I2C_SPEED_TO_DUTY(I2C_SPEED_MAX) + 1)
62 #define I2C_DUTY_MIN 0xff /* 8 bit limited */
63 #define SYS_I2C_DUTY I2C_SPEED_TO_DUTY(CONFIG_SYS_I2C_SPEED)
64 /* Note: duty is inverse of speed, so the comparisons below are correct */
65 #if SYS_I2C_DUTY < I2C_DUTY_MAX || SYS_I2C_DUTY > I2C_DUTY_MIN
66 # error "The I2C hardware can only operate 20KHz - 400KHz"
69 /* All transfers are described by this data structure */
72 #define I2C_M_COMBO 0x4
73 #define I2C_M_STOP 0x2
74 #define I2C_M_READ 0x1
75 int len; /* msg length */
76 u8 *buf; /* pointer to msg data */
77 int alen; /* addr length */
78 u8 *abuf; /* addr buffer */
81 /* Allow msec timeout per ~byte transfer */
82 #define I2C_TIMEOUT 10
85 * wait_for_completion - manage the actual i2c transfer
88 static int wait_for_completion(struct twi_regs *twi, struct adi_i2c_msg *msg)
91 ulong timebase = get_timer(0);
94 int_stat = readw(&twi->int_stat);
96 if (int_stat & XMTSERV) {
97 writew(XMTSERV, &twi->int_stat);
99 writew(*(msg->abuf++), &twi->xmt_data8);
101 } else if (!(msg->flags & I2C_M_COMBO) && msg->len) {
102 writew(*(msg->buf++), &twi->xmt_data8);
105 ctl = readw(&twi->master_ctl);
106 if (msg->flags & I2C_M_COMBO)
107 writew(ctl | RSTART | MDIR,
110 writew(ctl | STOP, &twi->master_ctl);
113 if (int_stat & RCVSERV) {
114 writew(RCVSERV, &twi->int_stat);
116 *(msg->buf++) = readw(&twi->rcv_data8);
118 } else if (msg->flags & I2C_M_STOP) {
119 ctl = readw(&twi->master_ctl);
120 writew(ctl | STOP, &twi->master_ctl);
123 if (int_stat & MERR) {
124 writew(MERR, &twi->int_stat);
127 if (int_stat & MCOMP) {
128 writew(MCOMP, &twi->int_stat);
129 if (msg->flags & I2C_M_COMBO && msg->len) {
130 ctl = readw(&twi->master_ctl);
131 ctl = (ctl & ~RSTART) |
132 (min(msg->len, 0xff) << 6) | MEN | MDIR;
133 writew(ctl, &twi->master_ctl);
138 /* If we were able to do something, reset timeout */
140 timebase = get_timer(0);
142 } while (get_timer(timebase) < I2C_TIMEOUT);
147 static int i2c_transfer(struct i2c_adapter *adap, uint8_t chip, uint addr,
148 int alen, uint8_t *buffer, int len, uint8_t flags)
150 struct twi_regs *twi = i2c_get_base(adap);
153 uchar addr_buffer[] = {
158 struct adi_i2c_msg msg = {
159 .flags = flags | (len >= 0xff ? I2C_M_STOP : 0),
166 /* wait for things to settle */
167 while (readw(&twi->master_stat) & BUSBUSY)
171 /* Set Transmit device address */
172 writew(chip, &twi->master_addr);
174 /* Clear the FIFO before starting things */
175 writew(XMTFLUSH | RCVFLUSH, &twi->fifo_ctl);
176 writew(0, &twi->fifo_ctl);
180 len = (msg.flags & I2C_M_COMBO) ? msg.alen : msg.alen + len;
181 writew(*(msg.abuf++), &twi->xmt_data8);
183 } else if (!(msg.flags & I2C_M_READ) && msg.len) {
184 writew(*(msg.buf++), &twi->xmt_data8);
189 writew(-1, &twi->master_stat);
190 writew(-1, &twi->int_stat);
191 writew(0, &twi->int_mask);
194 ctl = readw(&twi->master_ctl);
195 ctl = (ctl & FAST) | (min(len, 0xff) << 6) | MEN |
196 ((msg.flags & I2C_M_READ) ? MDIR : 0);
197 writew(ctl, &twi->master_ctl);
199 /* process the rest */
200 ret = wait_for_completion(twi, &msg);
203 ctl = readw(&twi->master_ctl) & ~MEN;
204 writew(ctl, &twi->master_ctl);
205 ctl = readw(&twi->control) & ~TWI_ENA;
206 writew(ctl, &twi->control);
207 ctl = readw(&twi->control) | TWI_ENA;
208 writew(ctl, &twi->control);
214 static uint adi_i2c_setspeed(struct i2c_adapter *adap, uint speed)
216 struct twi_regs *twi = i2c_get_base(adap);
217 u16 clkdiv = I2C_SPEED_TO_DUTY(speed);
219 /* Set TWI interface clock */
220 if (clkdiv < I2C_DUTY_MAX || clkdiv > I2C_DUTY_MIN)
222 clkdiv = (clkdiv << 8) | (clkdiv & 0xff);
223 writew(clkdiv, &twi->clkdiv);
225 /* Don't turn it on */
226 writew(speed > 100000 ? FAST : 0, &twi->master_ctl);
231 static void adi_i2c_init(struct i2c_adapter *adap, int speed, int slaveaddr)
233 struct twi_regs *twi = i2c_get_base(adap);
234 u16 prescale = ((get_i2c_clk() / 1000 / 1000 + 5) / 10) & 0x7F;
236 /* Set TWI internal clock as 10MHz */
237 writew(prescale, &twi->control);
239 /* Set TWI interface clock as specified */
240 i2c_set_bus_speed(speed);
243 writew(TWI_ENA | prescale, &twi->control);
246 static int adi_i2c_read(struct i2c_adapter *adap, uint8_t chip,
247 uint addr, int alen, uint8_t *buffer, int len)
249 return i2c_transfer(adap, chip, addr, alen, buffer,
250 len, alen ? I2C_M_COMBO : I2C_M_READ);
253 static int adi_i2c_write(struct i2c_adapter *adap, uint8_t chip,
254 uint addr, int alen, uint8_t *buffer, int len)
256 return i2c_transfer(adap, chip, addr, alen, buffer, len, 0);
259 static int adi_i2c_probe(struct i2c_adapter *adap, uint8_t chip)
262 return adi_i2c_read(adap, chip, 0, 0, &byte, 1);
265 static struct twi_regs *i2c_get_base(struct i2c_adapter *adap)
267 switch (adap->hwadapnr) {
268 #if CONFIG_SYS_MAX_I2C_BUS > 2
270 return (struct twi_regs *)TWI2_CLKDIV;
272 #if CONFIG_SYS_MAX_I2C_BUS > 1
274 return (struct twi_regs *)TWI1_CLKDIV;
277 return (struct twi_regs *)TWI0_CLKDIV;
280 printf("wrong hwadapnr: %d\n", adap->hwadapnr);
286 U_BOOT_I2C_ADAP_COMPLETE(adi_i2c0, adi_i2c_init, adi_i2c_probe,
287 adi_i2c_read, adi_i2c_write,
289 CONFIG_SYS_I2C_SPEED,
293 #if CONFIG_SYS_MAX_I2C_BUS > 1
294 U_BOOT_I2C_ADAP_COMPLETE(adi_i2c1, adi_i2c_init, adi_i2c_probe,
295 adi_i2c_read, adi_i2c_write,
297 CONFIG_SYS_I2C_SPEED,
302 #if CONFIG_SYS_MAX_I2C_BUS > 2
303 U_BOOT_I2C_ADAP_COMPLETE(adi_i2c2, adi_i2c_init, adi_i2c_probe,
304 adi_i2c_read, adi_i2c_write,
306 CONFIG_SYS_I2C_SPEED,